1. Field of the Invention
The present invention relates generally to filters, and more specifically to a fluid filter assembly for filtering fluids such as oils, fuels and lubricants.
2. Background of the Invention and Description of the Prior Art
Filters for the removal of particulates and contaminants from fluids are known. Likewise, filters for filtering oils, fuels and lubricants delivered to internal combustion engines, transmissions and other mechanical apparatus are known. The purpose and object of such filters is to remove dirt, debris and particulates that accumulate during operation and also to remove debris “thrown off” the mechanical components of the apparatus during operation. The filters separate and segregate the particulates, dirt and debris from the fluid to prevent those items from causing wear and damage to the mechanical apparatus, while permitting the fluids to continually flow through the filter for lubrication and cooling. Although there has been tremendous advancements in filter technology over the years, at least two problematic aspects of filtering fluids have remained unresolved, first determining when a fluid filter has become plugged with dirt, contaminants and particles such that the flow of lubricant therethrough is diminished/restricted, and second determining what has caused the filter to become plugged (e.g. dirt from normal usage or particulates that could be indicative of a failing component).
A variety of means and methods to detect when a fluid filter is becoming plugged with contaminants and the like have been developed. Most such means and methods use a change of fluid pressure to warn the user that the filter is becoming plugged. The change in fluid pressure may be an increase in fluid pressure going into the filter, or decrease in fluid pressure coming out of the filter. Other means rely on inspection windows or transparent construction of the filter to visualize the condition of the fluid passing therethrough.
Although sight windows and transparent construction have provided means to inspect some fluids, many sight windows and transparent construction methods have remained ineffective when the fluid to be inspected is opaque, such as engine oil, and modern lubricants that have a variety of additives therein. Opaque fluids make it impossible for a user to visualize contaminants or particles on a filter element without draining the fluid from the fluid filter assembly and the mechanical apparatus, which is a significant portion of the work involved with changing the fluid entirely. At least partially because of these continuing problems, most fluid filters are disposable and are replaced when the fluid is changed without any inspection of the filter element itself for particulates that may be indicative of a potential mechanical failure. Further, dirty/used fluid filters are classified as hazardous waste and proper disposal thereof is expensive.
Engine failures are commonly a result of bearing failure caused by lack of lubrication and lack of cooling. When lubricant flow ceases, or is significantly diminished, such as when a oil filter becomes “plugged” the bearings suffer excessive wear and generate excessive heat that exacerbates the wear and can ultimately lead to mechanical failure of the components and catastrophic engine damage. In other instances, mechanical components may fail and the operator will not be aware of the occurring failure until after a catastrophic event which may cost significant amounts of money to repair.
The fluid filter with a sight glass overcomes various of these problems by providing a fluid filter assembly having a first housing carrying a transparent sight glass, a screen filter visible through the sight glass, and a second housing sealed to the first housing and carrying a low pressure drain valve and a bypass valve.
The fluid filter assembly with sight glass is an early warning device allowing a user to determine if a problem is developing within a mechanical apparatus. In some instances the fluid filter assembly may allow a user to determine which particular component is the failing. For instance, if bearing material, or valve spring material is present on the filter element, it is indicative of those components failing.
The filter assembly flows fluid through an inlet opening then into plural radially spaced arcuate openings defined in a sight glass retainer that function as separate filters within the assembly. Each arcuate opening communicates fluid onto a portion of a screen filter exposed by each arcuate opening. The fluid flows through the filter element into mating arcuate recesses defined in a lower housing. The arcuate recesses in the lower housing communicate with plural fluid passages and with an outlet passage. The plural arcuate openings defined in the sight glass retainer have vertically extending fluid deflectors adjacent edge portions of the arcuate openings which catch dirt, contaminants and particulates, and distribute the fluid, dirt, contaminants and particles across the surface of the screen filter. The plural openings function as individual filters. If the screen filter of one opening becomes plugged the fluid will still flow through the remaining openings that have not plugged. In the event the entire screen filter becomes plugged sufficiently to restrict the flow of fluid through the screen filter, the fluid filter assembly has a bypass valve. The bypass valve will open if the pressure of the fluid rises to a predetermined pressure. When the bypass valve opens it allows fluid to flow therethrough without passing through the screen filter. Even though the fluid passing through the bypass valve is not being filtered it will still tend to prevent catastrophic failure caused by a complete absence of fluid flow.
The fluid filter assembly provides a means to visualize the screen filter element regardless of the type of fluid being filtered without the need to drain the fluid from the fluid system. The fluid filter assembly also has a low pressure drain valve which functions responsive to fluid pressure. When the filter assembly is pressurized, the low pressure drain valve closes forcing the fluid through the screen filter and out through the outlet opening and to the apparatus to which the fluid filter assembly is attached, e.g. an internal combustion motor. When fluid pressure is removed (e.g. the internal combustion motor is turned off), the low pressure drain valve opens which allows the fluid to flow out of the filter assembly and into a fluid reservoir, such as an oil pan. The fluid filter assembly also has a pressurized air input valve that allows a user to inject pressurized air into the filter assembly from a position above the screen filter which forces the fluid through the screen filter, and out through the outlet opening allowing a user to inspect the screen filter for contaminants and particulates. Pressurized air input eliminates the need to plumb an additional drain line to drain the assembly and forces opaque and/or viscous fluids through the screen filter leaving particulates and contaminants visible to a user for inspection and identification.
In a second embodiment the fluid filter assembly is modified to carry a removable disposable fluid filter on a bottom portion of the filter assembly. The addition of a removable disposable filter allows a user to filter microscopic particles out of a fluid and still allow a user to visually inspect the fluid and the screen filter for any larger particles trapped on a screen filter element visible through the sight glass. Other types of replaceable disposable fluid filters such as water separator may likewise be installed if a user desires to remove water from the fluid being filtered.
The ability to use a removable disposable fluid filter is important because various vehicle and equipment warranties may be voided unless a specific type of disposable fluid filter is used. The second embodiment of the filter assembly resolves this need for the user who wants to visually inspect for particles filtered out of a fluid and remain protected by vehicle or equipment warranties. The instant fluid filter will also extend the useful life of a disposable filter.
Some or all of the drawbacks and problems explained above, and other drawbacks and problems, not yet known or recognized may be helped or solved by the invention shown and described herein. The invention may also be used to address other problems not set out herein or which become apparent at a later time. The future may also bring to light unknown benefits which may be in the future appreciated from the novel invention shown and described herein.
The invention does not reside in any one of the identified features individually, but rather in the synergistic combination of all of its structures, which give rise to the functions necessarily flowing therefrom as hereinafter specified and claimed.